Tandem motor assembly

ABSTRACT

A PNEUMATICALLY DRIVEN MOTOR ASSEMBLY TO OPERATE A TOOL COMPRISING A PLURALITY OF SPACED IN-LINE MOTOR UNITS CONNECTED TO PRODUCE POWER ADDITIVELY, EACH OF THE MOTOR UNITS BEING POSITIONED IN AN OUT-OF-PHASE RELATIONSHIP WITH EACH OTHER.

Staten Pateni Inventor Appl. No. Filed Patented Assignee TANDEM MOTOR ASSEMBLY 3 Elnima, 7 Drnwilng 1i" ins.

.. 1F01c1l11/00 91/58,90,

11m. 1111 l ield o11Senreh.....

121; 253/1 1 l, 149, 67, 85, (lnquired); 173/(lnquired); 418/213, 212, 210

Rem-cum (31ml UNITED STATES PATENTS 2/1870 Fitzgerald 6/1890 Dow Primary Examiner-Martin P. Schwadron Assistant Examiner- Irwin C. Cohen Attorney-Robert 1E. Geauque ABSTRACT: A pneumatically driven motor assembly to operate a tool comprising a plurality of spaced in1ine motor units connected to produce power additively, each of the 91/121 motor units being positioned in an out-of-phase relationship 253/85 with each other.

44 44, Z? fil 72 M 2 a 0 5 5 L 7! M fi TANDEM MOTOR ASSIEMIBILY BACKGROUND OF INVENTION In manufacture of products it is common to employ tools such as drills, reamers, etc. which are operated pneumatically. The power supply usually comprises an air compressor or other form of a compressed gas. The driving motor assembly usually comprises a single motor unit with a common type of motor used being a vane motor.

l-Ieretofore, there have been several disadvantages in the use of such a single motor unit type of assembly; First, many tool operations require a substantial power output from the driving motor. To achieve a sufficient power output from a single motor unit requires a substantial increase in the physical size of the motor unit and as a result the entire assembly. Besides the increase in size making the unit difficult to handle and less likely to be operable in confined locations, there is also a corresponding increase in the motor assembly weight. It is well known that the heavier the assembly the quicker the operator tires. I

A second disadvantage is that in a single motor unit, it is not possible to achieve a nearly constant level of power output. It is known that in any type ofmotor, vane-type included, that as each chamber becomes exposed to the pressurized air, the power output is greatest initially and then decreases until the minimum level just prior to when the chamber is no longer exposed to the pressurized air. This causes an unsmooth operation, though not observable by the human eye, and it does affeet the quality ofwork produced.

It would be most desirable to design a tool which has a substantial power output, yet small in physical size and was smooth in operation.

SUMMARY OF THE INVENTION The tool assembly of this invention provides for the inclusion of a plurality of separate motor units to be connected ad ditively, Each of the motor units are identical with the preferred type of unit being a vane motor. The units are positioned in an out-of-phase relationship with each other so that maximum smoothness is achieved, that is, assuming two motor units, when a chamber of one motor unit is midway in its power stroke, a chamber of the second motor unit is initiating its power stroke.

Further, the rotational power produced buy the units is transmitted through a planetary gear system prior toits emission from the tool. This is necessary to provide for a reduction in velocity without loss of power and to insure smoothness of operation of the tool.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is a partly in section, cutaway side view of the connected motor units and associated structure ofthis invention;

FIG. 2 is an exploded perspective view of the motor unit assem blies employed in this invention;

FIG. 3 is a side view ofthe entire tool apparatus in which the structure ofthis invention would be employed;

FIG. 4 is an exploded view of the planetary gear system through which the power output from the motor units is transmitted;

FIG. 5 is a view taken along line 5-5 of FIG. ll showing the location ofthe rotor and its vanes'within the motor housing;

FIG. 6 is a view taken along line 66 of FIG. I showing the physical relationship of the second motor unit; and

FIG. 7 is a sectional view ofjust the motor housing of FIG. 6.

DETAILED DESCRIPTION OF THE SHOWN EMBODIMENT Referring particularly to the drawings, in FIG. 3 there is shown an exterior overall view of a portable motor assembly I0 embodying the motor units of applicant's invention. Assembly 10 includes a handle 12 for which to facilitate grasping by the human hand. The assembly 10 includes a drive shaft 114 which is capable of rotary motion and operating a drill or other type of tool (not shown). The drive shaft I14 5 supported by a cylindrical housing l6. A trigger valve assembly 116 is to permit the access or nonaccess of pressurized gas which effects the rotary motion of the drive shaft 14.

Referring particularly to FIGS. 1 and 2, the cylindrical housing 16 includes a motor housing 20 and an outer gear housing 22. Drive shaft 14 is rotatably supported by a bearing 24 which is securely retained within the outer gear housing 22. Drive shaft 14 isintegrally connected to a planet gear housing 26 which rotatably supports in its interior two planet gears 28 and 20 by means of pivot pins 32 and 34, respectively. Planet gears 23 and 30 are in a driving connection with ring gear 36 which is securely fixed to the outer gear housing 22. Planet gears 28 and 30 are driven by a first motor shaft 36 which is rotatably supported by dual bearing assembly 40. Bearing assembly 40 is retained within a bearing housing 42 which connects outer gear housing 22 and motor housing 20.

First motor shaft 36 is integrally connected to a first vane rotor 44 which includes a plurality of longitudinal radial slots 46 which are capable of retaining a movable vane 46. The radial edges of the movable vanes 48 are to be maintained in sliding contact with eccentric bore 50 within the cylinder wall 52. Upon rotation of motor 44 within bore 50 of cylinder wall 52, due to the eccentric relationship of bore 50 with respect to rotor 44, a chamber 54 of varying volume according to circumferential displacement is created. As pressurized gas (usually air) is caused to enter chamber 54 through the inlet ports 56, the volume of the space between adjacent vanes 48 increases thereby permitting additional volume of air to enter therebetween. This is assuming that the rotational direction of the rotor 44 is counterclockwise as depicted in FIG. 5. The space between the vanes increases until the lead vane reaches the point A which is 180 from the point of contaction, point B, of rotor 44 with bore 50 of wall 52. At this point air is no longer permitted to enter the chamber 54. Upon further rotational movement of rotor 44, it is readily apparent that the air retained within the adjacent vanes 48 will be compressed thereby hindering motor action unless some means of removal is permitted. Exhaust ports 58 are provided to permit removal of the exhaust air within chamber .54. This type of motor action is conventional and is termed a vane motor.

The other end of the first motor shaft 38 is splined through a sleeve 60 to a second motor shaft 62. Both the first motor shaft 38 and the second motor shaft 62 are supported by bearings 64 and 66, respectively, within spline housing 68. An annular air inlet chamber is created about spline housing 68. Second motor shaft 62 is connected to a rotor 72 which operates and is substantially identical in construction to the motor heretofore described. Rotor 72 includes slots 74 within which are to movably retain vanes 76. Vanes 76 are in sliding contact with the bore 76 of cylinder wall 80. An unbalanced chamber 82 is likewise created due to the eccentric relationship of rotor 72 with respect to bore 76. Pressurized air enters chamber 82 through the inlet ports 84 and is exhausted through the exhaust ports 86.

Besides the inventive concept of employing a plurality of motor units within a single motor assembly, the motor units are in an out-of-phase relationship with each other for the purpose of achieving smoother operation and a higher more constant power level. It is to be noted from the drawings that each rotor includes 5 (in number) vanes. That means that there is 72 spacing between adjacent vanes. When the pressurized air first contacts the space between adjacent vanes, the maximum force is created tending to effect rotation of the rotor. This force level steadily decreases until a minimum is reached at the point just prior to that space rotating out of association with the inlet. The power level then returns to the maximum due to a subsequent space between vanes coming into contact with the inlet. In an effort to smooth out these slight surges in power, one motor unit is positioned so that its vanes are located to come into contact with the inlet air pressure at a rotational distance of 36 from the vanes of the other motor unit (oneehalf of 72 Clearly, this relationship between the motor units insures a higher and more constant power level of the entire assembly plus a smoother operating assembly since the power outputs of the separate motor units are additively connected through spline 60.

It is to be understood that if three motor units were employed, each unit would be located 24 out-of-phase with each other. If four units, the relationship would be 18 and so forth.

The operation of the motor assembly of this invention is as follows. Pressurized gas, such as air, is supplied to the assembly from a source (not shown). The gas is permitted to pass through passage 88 to chamber 70 through activation of trigger valve assembly 18. The pressurized gas then enters the inlets of the respective motor units through apertures 90 and 92. The pressurized air then causes rotation of the rotors 44 and 72 thereby causing rotation of first motor shaft 38. To decrease the velocity of rotation while not decreasing the power output, the planetary gear system 26, 28 and 30 is employed prior to rotation of the drive shaft 14. The use of the planetary gear system is a prerequisite as the motor speed is too great to accomplish most tooling operations. A drill or other type of tool can be operated by connecting such to the drive shaft 14.

The pressurized air once it has performed the useful work upon the rotors 44 and 72 is exhausted to the atmosphere through exhaust ports 58 and 86, respectively. Each of the exhaust ports 58 and 86 consist of a plurality of spaced slots within their respective cylinder walls 52 and 80 to provide adequate volume of space for removal of the exhaust gases. Surrounding the exterior of each of the exhaust ports 58 and 86 are shields 94 and 96, respectively. Each of the shields includes apertures 98 too permit the exhausting gases passage to within the atmosphere. The function of the shields 94 and 96 is to prevent foreign material from entering the exhaust ports 58 and 86.

It is to be noted that each of the cylinder walls 52 and 80 are held rigid with respect to the motor housing 20 by means of pins 100 and 102, respectively. The unattached end of second motor shaft 62 is journaled by means of a bearing 104 which cooperates with a bearing housing 106 which in turn cooperates in a tight fitting relationship with the motor housing 20. A plate 108 functions to seal this portion of the motor housing 20.

lclaim:

l. A pneumatically driven motor assembly for operating rotary driven tools comprising:

a motor housing; a first motor unit within said motor housing including a first rotor being rotatable within a first casing, pressurized gas inlet means to permit passage of pressurized gas to within said first casing and causing rotation of said first rotor, exhaust ports within said first casing to effect removal of said gas after said gas has ex pended its useful energy;

a second motor unit within said motor housing including a second rotor together, rotatable within a second casing, pressurized gas inlet means to permit passage of pressurized gas to within said second casing and causing rotation of said second rotor, exhaust ports within said second casing to effect removal of said gas after said gas has expended its useful energy;

the outputs of said first and second motor units being additively connected together, said first motor being out-ofphase with said second motor with the out-of-phase relationship being selectable prior to installation, a fluid inlet chamber provided intermediate said first and second motor units and defined between said motor housing and a spline housing positioned in said motor housing, said inlet chamber further including passage means to supply inlet fluid simultaneously to both of said first and second motor units;

the output of said first rotor causing rotation of a first splined shaft, the output of said second rotor causing rotation of a second splined shaft, said first and secon shafts are splined together by a internally splined sleeve said first and second splined shafts and said sleeve being positioned within said spline housing;

the selectable out-of-phase relationship being determined by said spline connection of said sleeve, said spline connection permitting selection of various out-of-phase relationships; and

said inlet chamber being annular in configuration and surrounding said spline connecting sleeve, said annular chamber functioning to accumulate said pressurized gas prior to admission to said first and second motor units.

2. An apparatus as defined in claim 1 wherein:

said out-of-phase relationship being such that said second motor begins each of its power strokes approximately midway of each power stroke of said first motor.

3. An apparatus as defined in claim 2 wherein:

said first and second motor units comprise vane-type of motors with the vanes of each motor spaced apart 72, whereby each of the power strokes of said second motor initiates with the corresponding power stroke of said first motor being angularly displaced 36. 

